1. Field of the Invention
The present invention relates to a recording device such as an ink jet printer, and a control method therefor.
2. Description of the Background Art
Recording devices employing an ink jet printing system print images (dots) on recording media by ejecting ink from recording heads while moving the heads in the forward (outward) and backward (return) directions to attach ink to the recording media. Then, the recording media are transferred by transfer rollers, etc. in the sub-scanning direction (transfer direction) and recording is repeated in the main scanning direction (perpendicular to the transfer direction) to form entire images on the recording media.
However, with such a recording device, which prints an image formed by dots on a recording medium while moving the recording heads back and forth in the main scanning direction, images (dots) recorded while moving the record heads forward are easily misaligned with images (dots) recorded while moving the record heads backward.
Therefore, typically the timing of ejecting ink in the forward and backward directions is adjusted to cancel out such misalignment of printing. This adjustment of the timing of ejecting ink is conducted using predetermined adjustment patterns.
For example, in Japanese patent application publication no. 2004-358759 (JP-2004-358759-A), an outward pattern serves as a reference and a return pattern is superimposed on the outward pattern.
The outward pattern is a reference adjustment pattern formed when the recording head is moving outward and the return pattern is a pattern formed for adjustment when the head is returning. Next, the superimposed adjustment pattern is detected and an optimal adjustment pattern is determined by observation with the naked eye based on changes in the density and color of the detected adjustment pattern. Misalignment of images is corrected using the optimal adjustment pattern.